V. Sladek, J. Sladek, and R. van Keer, “New integral equation approach to solution of diffusion equation”, Comp. Assist. Methods Eng. Sci., vol. 9, no. 4, pp. 555–572, Feb. 2023, Accessed: Jun. 29, 2025. [Online]. Available: https://cames.ippt.pan.pl/index.php/cames/article/view/1118